1. Field of Technology
The disclosure relates generally to pumps, and more specifically, positive displacement pumps, such as reciprocating pumps applied to drilling mud and well service applications, and to radial valves used therein to control the flow of the pumped fluid into and out of such pumps. More particularly, the disclosure relates to a valve module for use in positive displacement pumps.
2. Background Information
Positive displacement pumps are used in various pumping applications. For example, reciprocating pumps are used in typical drilling operations to pressurize an abrasive slurry of solids and liquids known as drilling mud, which is then conveyed to the bottom of a borehole that is being drilled in the earth. The pressurized mud is used to maintain appropriate borehole pressure, lubricate and cool a downhole drill bit, and carry loosened sediment and rock cuttings from the borehole bottom to the surface. At the surface, the cuttings and sediment are removed from the returning drilling mud, and the now-filtered drilling mud may be recycled and pumped back to the borehole bottom.
Suction and discharge valves are used in reciprocating pumps to control the flow of fluid into and out of the pump's cylinders where the fluid is pressurized. Due to the highly abrasive nature of the particles often present in the slurry being pressurized, the valves and seals of the pumps must be designed to resist harsh abrasion, while maintaining positive sealing action under relatively high operating pressures. Additionally, the valve elements and the structural components retaining them in the pump are exposed to very high and cyclic pressures. For example, a valve module containing a valve assembly may pressurize, reaching up to 7,500 psi or more, and then may relieve down to 0 psi many times per minute. This high cyclic pressure changes generate stresses that can significantly impact the life of the components. It is common and expected that seals, gaskets, and other valve components will wear or fail requiring routine replacement and necessitating that the pump be shut down and repaired. Repairs to the valve module are time-consuming and expensive. The cost and time of maintenance and repairs are attributed in part to the construction of a conventional pump, which includes separate suction and discharge valve modules having separate assemblies for each valve within the modules. Removal and replacement requires handling of the multiple components. In addition, conventional pump designs result in bulky, heavy equipment.